Excavator bucket for underwater use

ABSTRACT

An excavator bucket has several embodiments adapted for use underwater. A first embodiment includes a front lip and a heel section, with suction ports through the heel section. Another embodiment includes a grated or skeleton bucket with apertures communicating with a suction hopper having suction ports. Yet another embodiment includes a drum grate rotating inside a fitted shroud offset from and conforming to a swept volume of the rotating grate, with the shroud having suction ports, and another embodiment includes a first hopper with rotating arbors forming a crushing screen, communicating with a second suction hopper having one or more suction ports.

CROSS REFERENCE TO RELATED APPLICATION

This non-provisional utility application claims the benefit of and priority to U.S. Provisional Application 62/829,344 “Excavator Bucket For Underwater Use,” filed 4 Apr. 2020. The entire contents of U.S. Provisional Application 62/829,344 “Excavator Bucket For Underwater Use,” filed 4 Apr. 2020 are hereby incorporated into this document by reference.

COPYRIGHT STATEMENT

A portion of the disclosure of this patent document contains material that is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever

FIELD

This invention relates to improvements in excavator buckets and mining methods. The invention also relates to excavator buckets operating underwater and optionally including cameras and lighting for remote viewing to assist with locating and excavating desirable material.

BACKGROUND

Underwater dredging and mining machinery includes the use of excavator buckets, however a limitation in this field is that most buckets in used are designed for land use where the solid material being broken up and extracted is primarily surrounded by air. These buckets fail to accommodate the hydrodynamic effects of water being so much denser than air and how the motions of rock or soil buoyed by water or salt water differ greatly from how this material is moved and collected on land in air.

BRIEF SUMMARY

Excavators and hydraulic equipment for mining and material transport use hydraulic actuators to move buckets designed to break up and collect solid materials. Depending on the extension and positioning of a boom carrying a bucket, there is a limit to the amount of material a bucket can carry before certain maximum threshold weight limits are reached. However, operational limits are broadened when working underwater because the materials comprising the bucket, the submerged portion of the boom, and the material carried in the bucket are all buoyed by the density of the water or seawater around them. It is therefore a primary objective of the invention to provide an excavator bucket capable of use underwater.

Another objective of the invention is apply the so that buoyancy provided by water assist with to separating, classifying, or recovering mined materials while these materials remain submerged.

BRIEF DESCRIPTION OF THE DRAWINGS

A further understanding of the nature and advantages of particular embodiments may be realized by reference to the remaining portions of the specification and the drawings, in which like reference numerals are used to refer to similar components. When reference is made to a reference numeral without specification to an existing sub-label, it is intended to refer to all such multiple similar components.

FIG. 1A shows an embodiment of an excavator bucket in accordance with the invention.

FIG. 1B shows the embodiment of the excavator bucket of FIG. 1A, showing suction ports in its heel section.

FIG. 2A shows an alternative embodiment of an excavator bucket in accordance with the invention.

FIG. 2B shows the embodiment of the excavator bucket of FIG. 2A, showing suction ports in its heel section.

FIG. 2C shows the suction hopper component of the excavator bucket of FIG. 2A and the inlets to its suction ports.

FIG. 3A shows another alternative embodiment of an excavator bucket in accordance with the invention.

FIG. 3B shows the embodiment of the excavator bucket of FIG. 3A with a suction port in the aft portion of its drum section.

FIG. 3C shows the embodiment of the excavator bucket of FIG. 3A with its rotatable grate exploded from its drum section.

FIG. 3D shows the embodiment of the excavator bucket of FIG. 3A having anti-cavitation apertures in its drum section.

FIG. 4A shows components of a rotatable arbor, and an arbor for another alternative embodiment of an excavator bucket in accordance with the invention.

FIG. 4B shows a set of rotatable arbors of FIG. 4A meshed together to define a crushing plane for an excavator bucket in accordance with the invention.

FIG. 4C shows an embodiment of excavator bucket in accordance with the invention, with its suction shroud removed to expose rotatable arbors meshed together in a crushing plane.

DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS

While various aspects and features of certain embodiments have been summarized above, the following detailed description illustrates a few exemplary embodiments in further detail to enable one skilled in the art to practice such embodiments. The described examples are provided for illustrative purposes and are not intended to limit the scope of the invention.

In the following description, for the purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the described embodiments. It will be apparent to one skilled in the art, however, that other embodiments of the present invention may be practiced without some of these specific details. Several embodiments are described herein, and while various features are ascribed to different embodiments, it should be appreciated that the features described with respect to one embodiment may be incorporated with other embodiments as well. By the same token, however, no single feature or features of any described embodiment should be considered essential to every embodiment of the invention, as other embodiments of the invention may omit such features.

In this application the use of the singular includes the plural unless specifically stated otherwise, and use of the terms “and” and “or” is equivalent to “and/or,” also referred to as “non-exclusive or” unless otherwise indicated. Moreover, the use of the term “including,” as well as other forms, such as “includes” and “included,” should be considered non-exclusive. Also, terms such as “element” or “component” encompass both elements and components comprising one unit and elements and components that comprise more than one unit, unless specifically stated otherwise.

The invention is an excavator bucket which includes several embodiments adapted for use underwater. A first embodiment includes a front lip and a heel section, with suction ports through the heel section. Another embodiment includes a grated or skeleton bucket with apertures communicating with a suction hopper having suction ports. Yet another embodiment includes a drum grate rotating inside a shroud which generally conforms to and is offset within an outer swept volume of the rotating grate, with the shroud also having suction ports, and another embodiment includes a first hopper with rotating arbors forming a crushing screen, communicating with a second suction hopper having one or more suction ports.

Suction ports are connected to suction lines or suction hoses, which are designed to not collapse when their internal pressure is substantially less than the environment around them. Suction lines are in turn connected to a suction pump also called a dredge pump, which in this specification is any pump, suction pump, or gravel pump capable of transporting a mixture of liquid and solid materials commonly called a slurry.

An excavator in this specification includes any type of crawling machine, tracked or wheeled vehicle, or skid steer or “donkey” or loader designed to move materials. A bucket in this specification may include a conventional excavator bucket, a skeleton bucket, or a screening bucket, any of which may be further equipped with vibrating generating machinery, flotation apparatus such as buoys or hollow vessels, or floats which may comprise closed cell foam or one or more compartments containing trapped air or a vacuum. Flotation aids may be directly affixed to a bucket or attached such as by chain so that a much smaller machine or smaller power machine may manipulate the bucket and may eliminate need for a counterweight. Flotation reduces the net relative weight felt at the boom end or stick end, so that a larger bucket may be used than is typically specified by an excavator or bucket manufacturer for on-land use.

In operations using inventive bucket embodiments which are built up by adding claimed components and features of the invention to simple bucket made by existing manufacturers, the limits listed in a given bucket manufacturer's lifting charts may be less relevant, in that a larger capacity bucket may be used because when loaded or filled the bucket is not being lifted, but rather only being rolled or “knuckled under” while being at least partially supported by the seabed. The bucket is then emptied such as by sucked clean by dredge suction line on or near seabed.

In this sort of operation, initial classification occurs on site within the bucket. The bucket almost never needs to be raised while containing material and almost never needs to be pivoted out of water, where time and much material is often lost when using conventional methods.

Machinery which provides vibration to a bucket not only helps classify or release material therein, but may also assist in ground engagement, such as being used to sink into clay.

Some excavators include counterweights on booms extending from the central mass of the machine in a direction substantially opposite to the stick and the boom which manipulate the excavator bucket. The counterweight may be fixed on a boom, or designed to be adjustable or may be attached to actuators which can move it dynamically in response to the weight and moment of the material in the bucket and the articulation of the boom and stick in operation. The moving or sliding counterweight extends when boom or stick retracts, and retracts when boom or stick extends, to reduce excursion the center of mass of the entire system, and to help keep excavator platform level.

A fixed counterweight may be deployed at an intermediate but adjustable position along its own boom or beam, and set or reset periodically based an average or an estimate of the toppling moment to be countered, so that an excavator can grab material in its bucket and lift it safely without toppling over.

Selection of the type or style of bucket for the work to be done is often conditioned by the consistency or types of materials encountered. Besides removal, extraction or displacement of material, a bucket may be used for separation or classification of materials by size, and by density especially if used underwater. Classification means the separation and sorting of constituents of a substance or a mass of material, usually by size or density.

Furthermore, an excavator and bucket system for underwater use may include cameras and underwater lighting so that an operator outside the water may view the excavation site and the operation of the machinery even while the water is cloudy or turbid, or while operating at night.

According to one mode of operation, a floating platform includes a detachable platform which carries an excavator machine and which may be lowered onto or close to a seabed from a floating vessel. Then the excavator may operate from a platform or may alternatively be driven off platform onto a seabed and back on to platform for retrieval. Seabed in this specification may also include any other submerged soil or work surface such as a lake bed or a river bed. Thus the excavator may be a submerged excavator or other earth and materials moving equipment modified to operate underwater and at depth.

Another problem addressed by the invention is that of preventing cavitation. Partial vacuum in swiftly moving fluid in the vicinity of solid surfaces such as suction ports, changes in flow cross sections in piping, or a dredge pump impeller may actually boil the water at ambient temperature. Once the bubbles form and are carried to a location of lesser vacuum or of positive pressure, they collapse violently and contribute to pitting and wearing away of solid surfaces in the vicinity of the implosions. Cavitation also causes undesirable noise and wastes energy.

In a bucket in accordance with the invention, countermeasures against cavitation damage include tubes, vents, or passages which admit water close to the screening choppers or rotary hammers or closely downstream thereof.

Another typical mining operation using excavators is to dislodge material from a mining face or surface being mined and to transport it to a wash plant, where flowing water may break up aggregate and separate materials by density. In these operations time is lost during raising, lowering, and swings of the bucket to and from a wash plant. Wash plants themselves consume a lot of energy and are prone to frequent mechanical breakdowns. Typically, the circulation of wash water at a wash plant and the power consumed by its pumps is continuous while deposits of material to be washed out and classified occur as pulses of input punctuated by dwell times where the bucket is moving but the wash plant has little or nothing to do. Typical operations incur inefficiencies because hydraulic pumps remain at work and consuming energy during the entire cycle, and fossil-fuel-powered generators for vibratory separators and other machinery are also running constantly, while material only arrives in periodic charges. The invention reduces these intervals of time between charges of materials being processed.

In operations in accordance with the invention, the work done by the wash plant is instead performed by the dredge pump itself. The energy supplied to the pump is directed more efficiently because wash plant pump may (in an example) be transporting and dispersing material for only 10% of its running time and the rest of the time it is moving water unrelated to the work and benefit gained by material separation means. The invention thus reduces these alternating cycles of production idleness, increasing operational efficiency and the amount of material processed per unit of energy expended.

Another source of improved efficiency using the invention is that initial classification occurs at the production zone. In this specification the production zone includes a point of initial acquisition of materials, a point of origin of materials being sought, or a zone where naturally sized materials as encountered are first broken up by mechanical or hydraulic means.

Depending on the consistency of the material encountered, the invention may even eliminate the need for a washing plant entirely. In summary the invention reduces energy wasted by raising material, moving the mass of the bucket and its boom or stick, and lowering the boom with an empty bucket. These parasitic dead weights moving up and down waste power and fuel.

Furthermore, clamshell buckets often lose material coming up out of the water or moving laterally in water. Instead, in operations in accordance with the invention the bucket may be partially supported by a production surface while knuckling under so that in concert with buoyant forces the excavator may manipulate a larger bucket than is typically specified in a given manufacturer's recommended size and weight limits for buckets attached to excavators.

These limits arise from the kinematics of stability and prevention of toppling of extended or cantilevered loads. Loads partially supported by a seabed may remove some constraints to the stability equation and thus allow for larger or heavier loads and allow the use of larger buckets than are commonly recommended on land.

Thus the operating limits of the invention are of greater scope than for on-land or unsupported situations, because in those typical operations, the excavator has limited extension while manipulating a heavy or filled bucket.

In contrast, in operations in accordance with the invention the dredge pump empties bucket without needing to move bucket far away from a production site, which also reduces in-transit loss of material. Thus the invention enables a new method of mining using a screening bucket with a dredge pump, and these combinations of increased bucket capacity and reduced cycle time increase production volume and operation efficiency.

Now proceeding to the figures, FIG. 1A shows an embodiment of an excavator bucket [10] in accordance with the invention. The bucket is a fabrication comprising a first side section [2] and a second side section [2′,] a curved heel section [9,] and a top section [4] joining the first side section, the second side section, and the curved heel section, and a lip [6] which joins the heel opposite from the top section. The lip also joins the first side section and said second side section, so that a perimeter comprising an edge of the top section, an edge of the first side section, an edge of the second side section, and an edge of the lip define a scoop plane which is also the mouth of the excavator bucket. The side sections are also called cheeks of a bucket.

The heel section further comprises at least one and in this case two apertures [5] which are suction tubes adapted for connection to a suction hose or a dredge line.

For countermeasures against cavitation, the upper corners of the excavator bucket each have a tube [7] there affixed, and substantially perpendicular to the scoop plane, where “substantially perpendicular” may be defined to mean “within 30° of perpendicular.” In cases or times of extreme vacuum conditions near the suction tubes, additional water may be admitted by passing through the tubes and bypassing the material collected in the bucket, so as to collapse or prevent bubble formation.

Given a suitable tube diameter and outside diameter, each tube may preferably have its axis at a distance within two outside diameters of a side section and the top section. Flow of water through these anti-cavitation tubes may create unnecessary suction immediately ahead of the tube, which may lead to unwanted material or foreign objects accruing or becoming lodged in the forward facing inlet of the tube. To reduce this occurrence, a plate [8] is affixed ahead of each anti-cavitation tube and preferably the space between the forward-facing inlet and the plate is equal to or less than the inner diameter of the tube. Any material passing around the plate and entering the tube should thus be able to travel within the tube without hanging up or creating an obstruction. The excavator bucket also includes brackets [3] for attachment to an excavator boom.

FIG. 1B shows the embodiment of the excavator bucket of FIG. 1A, showing suction ports [5] in its heel section. The cheeks [2] of the bucket may optionally include patterns of hard facing [14] material typically deposited or applied by electric arc welding machines.

FIG. 2A shows an alternative embodiment of an excavator bucket [20] in accordance with the invention. The embodiment shown here is based on a skeleton bucket wherein the heel, and optionally the lip [6,] and optionally the cheeks [2] also are perforated by slots, holes or apertures. The skeleton bucket may also be formed as a grille. The bucket may also include brackets [3] for attachment to an excavator boom.

As with the previous embodiment, anti-cavitation tubes [7] are located at the upper corners of the bucket and protected by plates [8] positioned ahead of their inlets. The bucket embodiment shown also has a shroud membrane [12] below the box section of the bucket or conformed to or proximal to the contour of the underside of a portion of the heel which contains through-apertures or slots [9] and optionally also extending to an underside portion of the lip where through-apertures or slots may also reside. At least one suction port [5] exits the shroud membrane or the end wall of the enclosure, and is adapted for connection to a suction hose or a dredge hose connected to a dredge pump.

FIG. 2B shows the embodiment of the excavator bucket of FIG. 2A, showing suction ports [5] in a shroud membrane [12] of its heel section. The shroud membrane conforms to the contour of the discharge portion of bucket or to the perimeter of a rotary screening bucket.

In an alternative embodiment, the shroud membrane may include collecting surfaces which are conical internal surfaces for inducting broken up material into the suction hoses attached to the bucket.

Thus an excavator bucket according to the embodiments of FIGS. 2A and 2B has a perforated trough membrane spanning between cheeks at both its ends, a shroud membrane spaced apart from and conforming to the perforated trough membrane, a perimeter wall connecting a perimeter of the perforated trough membrane to a perimeter of the shroud membrane, and a shroud membrane further comprising at least one aperture and preferably a large plurality of apertures or slots.

FIG. 2C shows the shroud membrane [12] which may also be called a suction hopper component of the excavator bucket of FIGS. 2A and 2B. The suction hopper has a floor [15] which with the shroud membrane and two enclosure walls [16] are spaced apart from the grille or perforated membranes of the bucket seen in FIGS. 2A and 2B. The suction ports [5] pierce the floor of the suction hopper.

The embodiments shown in FIGS. 2A, 2B, and 2C, may be summarized as an excavator bucket for underwater use having a perforated trough membrane spanning between cheeks at both its ends, a shroud membrane spaced apart from and conforming to the perforated trough membrane, a perimeter wall connecting a perimeter of the perforated trough membrane to a perimeter of the shroud membrane, and with the shroud membrane further comprising at least one aperture, but preferably a large plurality of apertures or a grille. The excavator bucket includes suction ports adapted for connection to a suction hose, which may be one or more apertures passing through the perimeter wall. At least one of the cheeks may also further comprise at least one aperture for reduction of cavitation effects.

The embodiments shown in FIGS. 2A, 2B, and 2C, hold a number of advantages in operation and especially in underwater operation. First, the device acts as a screening bucket which may chew up a lot of clay or similar compacted materials or aggregates. Second, material in transit within the suction line to the dredge pump moves at such a high flow rate that aggregates may be further broken up prior to them hitting a sluice or other classifying, milling, or separating equipment downstream of the excavator. Third, a screening bucket in action as a pre-classifier or separator may eliminate the need for other energy-consuming equipment such as a trommel or vibratory wash plants. Fourth, by breaking up material into smaller chunks, impact damage from dropping rock into hoppers and impacts onto equipment is reduced. For example, impacts of 40 lbm rocks falling onto metal or poly plates are eliminated, and these impacts can really beat up equipment over time. Lastly, breaking up material into smaller chunks and screening out larger, obdurate rocks reduces the chance of having objects obstruct the suction line.

FIG. 3A shows another alternative embodiment of an excavator bucket [30] in accordance with the invention. The front lip includes replaceable teeth {17] which may, of course, be affixed to the other embodiments shown and described in this specification. Cheeks [2] are affixed on both sides of the lip, and the bucket is formed as a collection hopper leading to a rotating grate [25] which resides within a drum section of the bucket which conforms to the contour of the rotating grate. The top section [22] of the bucket includes brackets [3] for attachment to an excavator boom.

FIG. 3B shows the embodiment of the excavator bucket of FIG. 3A with a suction port in the aft portion of its drum section, and with the end wall of the drum section [26] further comprising at least one aperture [5] adapted for attachment for a suction hose. In this view the rotating grate [25] and some of its apertures are visible through the suction port. A dredge suction hose may also be attached to one or more apertures in end wall of enclosure.

FIG. 3C shows the embodiment of the excavator bucket [30] of FIG. 3A with its rotatable grate [25] exploded from its drum section [26.] The grate has a plurality of apertures [28] and defines an axis of rotation [29.] The excavator bucket for underwater use has a hopper section connected to the drum section and a rotating perforated barrel having an open end and a closed end, rotationally coupled within the drum section, which is closed by an end wall opposite the hopper section.

FIG. 3D shows the embodiment of the excavator bucket [30] of FIG. 3A having anti-cavitation apertures [32] in its drum section [26.] According to a preferred embodiment, the drum section further comprises at least one aperture proximate to the hopper section within 15% of the length of the drum section.

FIG. 4A shows components of a rotatable arbor [35,] defining an axis of rotation, which is a built-up arbor [35] for yet another alternative embodiment of an excavator bucket in accordance with the invention. In one kind of embodiment, the arbor includes a series of spaced apart plates, of which some are simple discs [34.] Other discs [31, 31′] further comprise at least one radially extending eccentric protuberance [33.] Alternatively, an arbor may also have a spaced apart series of disc plates [34] and have a plurality of breaker bars extending radially from between the plates. Also alternatively, any one or more plates which have perimeter contours that include radially extending eccentric protuberances may comprise an ovoid, a cardioid, a regular polygon, an irregular polygon, an epicycloid, or an epitrochoid as a portion or an entirety of its perimeter.

FIG. 4B shows a set of rotatable arbors [35] meshed together to define a crushing plane for an excavator bucket in accordance with the invention. The plates of adjacent arbors interdigitate so that the protuberances act as breaker bars driving bits of broken up material between the series of spaced-apart plates.

FIG. 4C shows an embodiment of excavator bucket [40] in accordance with the invention having a suction shroud [38] removed to expose rotatable arbors [35] meshed together in a crushing plane. The excavator bucket has a first hopper section [36] defining and tapering to the crushing plane and defining an axis perpendicular to the crushing plane. At least one rotatable arbor [35] operates within the crushing plane, and in this particular illustration there are four interdigitated or meshed rotating arbors. The second hopper section is the suction shroud which includes enclosure walls [37] attached to and extending from the hopper at the crushing plane and enclosing the set of rotatable arbors. One or more rotatable arbors may reside at least partially within the enclosure.

Furthermore, the enclosure further comprises at least one aperture [5] which is adapted for connection to a suction hose. The enclosure may also include additional apertures for cavitation reduction, and the hopper section may also further comprise at least one aperture for cavitation reduction.

While certain features and aspects have been described with respect to exemplary embodiments, one skilled in the art will recognize that numerous modifications are possible. Further, while various methods and processes described herein may be described with respect to particular structural and/or functional components for ease of description, methods provided by various embodiments are not limited to any particular structural and/or functional architecture.

Hence, while various embodiments are described with or without certain features for ease of description and to illustrate exemplary aspects of those embodiments, the various components and/or features described herein with respect to a particular embodiment may be substituted, added, and/or subtracted from among other described embodiments, unless the context dictates otherwise. Consequently, although several exemplary embodiments are described above, it will be appreciated that the invention is intended to cover all modifications and equivalents within the scope of the following claims. 

What is claimed is:
 1. An excavator bucket for underwater use, having: a first side section and a second side section, a curved heel section, and a top section joining the first side section, the second side section, and the curved heel section, a lip joining said heel section opposite said top section, said lip also joining said first side section and said second side section, such that a perimeter comprising an edge of said top section, an edge of said first side section, an edge of said second side section, and an edge of said lip defines a scoop plane and a mouth of said excavator bucket, a first tube having an outside diameter and attached within said excavator bucket substantially perpendicular to said scoop plane, said first tube having its axis at a distance within two outside diameters of said first side section and said top section, a second tube having an outside diameter and attached within said excavator bucket substantially perpendicular to said scoop plane, said second tube and having its axis within two outside diameters of said second side section and said top section, and said heel section further comprising at least one aperture adapted for connection to a suction hose.
 2. The excavator bucket of claim 1, further comprising a plate occluding at least a portion of said first tube.
 3. The excavator bucket of claim 1, further comprising a plate occluding at least a portion of said second tube.
 4. The excavator bucket of claim 1, further comprising a vibratory mechanism.
 5. An excavator bucket for underwater use, having: a perforated trough membrane spanning between cheeks at both its ends, a shroud membrane spaced apart from and conforming to said perforated trough membrane, a perimeter wall connecting a perimeter of said perforated trough membrane to a perimeter of said shroud membrane, and said shroud membrane further comprising at least one aperture.
 6. The excavator bucket of claim 5, wherein said aperture in said shroud membrane is adapted for connection to a suction hose.
 7. The excavator bucket of claim 5, wherein said perimeter wall further comprises at least one aperture.
 8. The excavator bucket of claim 5, wherein at least one of said cheeks further comprises at least one aperture.
 9. The excavator bucket of claim 5, further comprising a vibratory mechanism.
 10. An excavator bucket for underwater use, having: a hopper section connected to a drum section closed by an end wall opposite said hopper section, said end wall of said drum section further comprising at least one aperture adapted for attachment for a suction hose, and a rotating perforated barrel having an open end and a closed end, rotationally coupled within said drum section.
 11. The excavator bucket of claim 10, wherein said drum section further comprises at least one aperture proximate to said hopper section within 15% of a length of said drum section.
 12. The excavator bucket of claim 10, further comprising a vibratory mechanism.
 13. An excavator bucket for underwater use, having: a hopper section defining a crushing plane and an axis perpendicular to said crushing plane, at least one rotatable arbor operating in said crushing plane, said rotatable arbor defining an axis of rotation and comprising a plurality of plates spaced apart along said axis of rotation, said rotatable arbor further comprising at least one radially extending eccentric protuberance, and an enclosure extending from said hopper, said enclosure further comprising at least one aperture.
 14. The excavator bucket of claim 13, wherein said hopper section further comprises at least one aperture.
 15. The excavator bucket of claim 13, wherein said aperture in said enclosure is adapted for connection to a suction hose.
 16. The excavator bucket of claim 13, wherein at least one of said plates comprises a perimeter shape selected from the set of shapes consisting of: a circle, an ovoid, a cardioid, a regular polygon, an irregular polygon, an epicycloid, and an epitrochoid.
 17. The excavator bucket of claim 13, further comprising a vibratory mechanism.
 18. The excavator bucket of claim 13, wherein said rotatable arbor resides at least partially within said enclosure. 